The invention relates to a drum scanner with a loading magazine for copy cylinders.
The published European Patent Document EP 0 270 011 B1 describes a drum scanner wherein a number of copy cylinders with longitudinal axes disposed horizontally are placed in a loading magazine formed as an uprightly standing rotary disk. Each of the copy cylinders, respectively, is disposed in a scanning position wherein it is rotated at one end about the longitudinal axis thereof while a carriage bearing a scanning element is moved parallel to the axis of the copy cylinder. This drum scanner is able to scan a number of copy cylinders one after another automatically. In a further embodiment, a horizontally movable loading magazine from which, respectively, a copy cylinder can be removed by a robot arm and, after being rotated about a number of axes, can be set onto a holding and rotating device.
In the conventional drum scanner with a loading magazine, it is not possible for the operator of the drum scanner to place copy cylinders into the loading magazine or to remove them therefrom during the continuous scanning operation, because the effects of shocks on the loading magazine are transmitted to the copy cylinder then being scanned or to the sensing element, which can have a detrimental influence upon the scan result. In the heretofore known embodiment with a robot arm, although changing a magazine during continuous operation would be conceivable if the subassemblies are sufficiently stable and solid, the construction and the control of the robot arm are relatively expensive and complicated.
It is accordingly an object of the invention to provide a drum scanner and loading magazine combination which avoids the foregoing disadvantages of heretofore known constructions of this type.
With the foregoing and other objects in view, there is provided, in accordance with the invention, in combination, a drum scanner and a loading magazine, the drum scanner comprising a holding and rotating device equipped for holding an interchangeable copy cylinder firmly from below in an at least approximately upright position and for rotating it about a longitudinal axis thereof for scanning, and the loading magazine being constructed for containing a plurality n of magazine spaces equipped for holding copy cylinders in the same orientation and at the same height as on the holding and rotating device of the drum scanner, the n magazine spaces and the holding and rotating device being arranged at regular intervals around a cylinder transport carousel having n+1 outriggers extending in a star-shaped manner relative to the n magazine spaces and the holding and rotating device, and being equipped for lifting, together with the aid of the outriggers, copy cylinders located in the n magazine spaces and on the holding and rotating device, respectively, for moving them in a circle and for setting them down again at a desired location, the drum scanner and the loading magazine being separable subassemblies connected mechanically to one another by connecting elements with vibration-damping properties, and being, respectively, provided with at least one foot for bearing the weight virtually of the respective subassembly.
In accordance with another feature of the invention, the cylinder transport carousel is fixed to the drum scanner and is not in contact with the loading magazine in any position.
In accordance with a further feature of the invention, each magazine space includes an annular antenna having an axis coinciding with the longitudinal axis of a copy cylinder located in the magazine space, each of the copy cylinders having a transponder on the underside thereof wherein an electronic file name is stored which can be read out and rewritten via the antenna.
In accordance with an added feature of the invention, each of the copy cylinders bears a barcode as an optical file name, and the drum scanner includes a barcode reader equipped for reading the barcode from a respective copy cylinder rotating on the holding and rotating device, the electronic file name of the respective copy cylinders being normally identical with the optical file name thereof.
In accordance with a concomitant feature of the invention, the drum scanner and the loading magazine are equipped for accommodating and for processing copy cylinders with different diameters.
Thus, a drum scanner according to the invention includes a holding and rotating device which is equipped for holding an interchangeable copy cylinder firmly from below in an at least approximately upright position and for rotating it about its longitudinal axis for scanning. A loading magazine for the drum scanner contains a number n of magazine spaces which are equipped to hold copy cylinders in the same orientation and at the same height as on the holding and rotating device of the drum scanner. The n magazine spaces and the holding and rotating device are arranged at regular intervals around a cylinder transport carousel which has n+1 outriggers, which extend in a star shape in relation to the n magazine spaces and the holding and rotating device. The cylinder transport carousel is equipped for lifting copy cylinders, which are located in the n magazine spaces of the holding and rotating device, together with the aid of the outriggers, to move them in a circle and to set them down again at a desired location. The drum scanner and the loading magazine are subassemblies which can be separated from one another, are connected mechanically to one another by connecting elements with vibration-damping properties, and each of which is provided with one or more feet which essentially bear the weight of the respective subassembly.
The invention makes it possible for the operator of the drum scanner, during continuous scanning operation, to place copy cylinders into the loading magazine or to remove them therefrom. As noted hereinbefore, in a conventional drum scanner with a loading magazine, this is not possible, because the effects of shocks on the loading magazine are transmitted to the copy cylinder then being scanned or to the sensing element, which can have a detrimental influence upon the scan result. In the known embodiment with a robot arm, although changing a magazine during continuous operation would be conceivable if the subassemblies are sufficiently stable and solid, the construction and the control of the robot arm are relatively expensive and complicated.
Decoupling the vibrations of drum scanner and loading magazine according to the invention permits the changing of copy cylinders during production or continuous operation without requiring that the subassemblies be particularly stable or solid. The possibility of changing copy cylinders during production or continuous operation means that the operator can adapt the flow of work to the then current requirements, because he or she can change the copy cylinders at any time without having to wait until the drum scanner is at a standstill or is switched off. It is therefore possible for the working sequence to be configured very flexibly.
The vibration-damping connecting elements hold the two subassemblies at least approximately in the correct position in relation to one another. Shocks when changing copy cylinders in the loading magazine are not transmitted to the drum scanner, but are absorbed by the base upon which the loading magazine is supported. A cylinder or roller change is thereby possible at any time, at least if it is performed carefully. A careful roller change is made easier by the fact that the copy cylinders stand at least approximately upright and can be set in place from above.
The at least approximately upright position of the copy cylinders, both in the loading magazine and in the drum scanner, additionally makes it possible to use a cylinder transport carousel, which represents a considerably simpler transport device than the robot arm disclosed by the prior art. In order that the cylinder transport carousel may be able to fulfill its function without any risk that it will transmit shaking of the loading magazine to the drum scanner, it can be fixed either to the drum scanner or to the loading magazine, so as not to come into contact with the respective other subassembly in any position. In a preferred embodiment, the cylinder transport carousel is fixed to the drum scanner, specifically in the vicinity of a casting which forms a base for the holding and rotating device.
Because of the vibration-damping connecting elements, the drum scanner and the loading magazine can move a little relative to one another. The accuracy required for inserting a copy cylinder correctly into the drum scanner can, however, easily be achieved by guides and interrogation elements. Suitable as guides are, for example, tapered, i.e., self-centering, cylinder holders in the drum scanner or loading magazine, and suitable as interrogation elements are, for example, light barriers or sensors for registering the position of the cylinder transport carousel.
Although the vibration-damping connecting elements do not prevent the shocks occurring during a change of the copy cylinder in the drum scanner from getting into the drum scanner as well, this does not lead to any disruption, because changing the copy cylinder in the drum scanner can necessarily be performed only in the scanning pauses.
The construction as separate subassemblies offers the additional benefit that existing drum scanners can be retrofitted with the loading magazine without difficulty, and that the loading magazine can easily be disassembled again if it is not needed.
In conjunction with the possibility of being able to change copy cylinders at any time, it is moreover advantageous for each magazine space to contain an annular antenna having an axis which coincides with the longitudinal axis of a copy cylinder located in the magazine space, and each copy cylinder has a transponder, on the underside thereof, wherein an electronic file name is stored which can be read out and rewritten via the antenna.
The antenna at each magazine space makes it possible to identify all the copy cylinders stored in the loading magazine at any time. As a result, it is also possible, without difficulty, to remove any desired copy cylinder from the loading magazine at any time and to reinsert it. If, for example, a copy cylinder is removed from the loading magazine after a prescan (coarse scanning), this can be detected by the scanner control system, and a fine scan (fine scanning) is not performed until the scanner control system detects that the corresponding copy cylinder is again located in the loading magazine. In this regard, it does not matter at which magazine space the temporarily removed copy cylinder is replaced.
If any copy cylinder which has newly arrived is to be scanned first, it can be placed on any free magazine space and, if the loading magazine is full, it can be interchanged with any copy cylinder which has not yet been scanned or has been scanned only roughly. In order to scan the new copy cylinder, the current operating sequence is simply interrupted at a suitable location, and the new copy cylinder is transported into the rotating and holding device with the aid of the cylinder transport carousel, is scanned there and then conveyed back to a free magazine space. After that, the original operating sequence can immediately be resumed automatically. If the operator forgets to replace the temporarily removed copy cylinder in any magazine space, the scanner control system can draw attention thereto with a warning signal.
Copy cylinders for drum scanners normally have a hollow shaft, so that an identification device, like the transponder, cannot be fitted centrally. The annular antennas make it possible to read the code from such copy cylinders in any position in relation to a magazine space. As a result, it is neither necessary for the operator to pay attention to a specific angular position when inserting an copy cylinder, nor is it necessary to move the copy cylinder in any way in order to read the file name, as is necessary in the prior art.
The use of a freely programmable transponder makes it possible to retrofit existing drum scanner systems without a loading magazine, wherein each copy cylinder bears a barcode as an optical file name which is read optically in the rotating and holding device of the scanner, with a loading magazine without difficulty. The optical file name can remain the governing file name, even after the retrofit.
If the scanner control system determines, in the case of a copy cylinder located in the rotating and holding device, that the electronic file name thereof, which has previously been read in the loading magazine, does not agree with the optical file name, the copy cylinder is then transported to a free magazine space with the aid of the cylinder transport carousel, and is there provided with the appropriate electronic file name before it is processed further.
The transponders used, respectively, have a chip which stores the electronic file name and, preferably, further data such as features of the copy cylinder and/or comments. The electronic file name and, if necessary or desirable, further data can be read or rewritten via high-frequency signals from the antenna. The chip does not have its own power supply, but is supplied with power via the high-frequency energy which the antenna radiates.
The arrangement of the transponder according to the invention makes it possible to equip the holding and rotating device and the loading magazine in such a way that copy cylinders with different diameters can be processed.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a drum scanner with loading magazine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: